Highway 12 widening project enters final phase

Motorists driving on Highway 12/Jameson Canyon Road between Highway 29 in Napa County and Red Top Road in Solano County will notice an increase in construction equipment during the next two months as the Highway 12 Jameson Canyon Widening Project enters the final stages.

The intent of the overall widening project is to add a lane of traffic in each direction, widening two lanes of traffic into four lanes with a concrete median. It is a much-awaited action for many motorists who have been wary of the dangers of driving on the two-lane road.

Elias Moussa, senior transportation engineer with the California Department of Transportation, said that beginning Aug. 1, eastbound traffic on the Solano County side of Highway 12, will be diverted to a new paved road which splits from the westbound lanes of traffic so 2,400 feet of barriers can be installed.

Moussa said it will take nine days for construction crews to build the barrier, which will then be sculpted to match the other two sculpted barriers already completed.

Traffic will be limited to one lane each way, as heavy construction equipment will need access to the road and space to move around, Moussa said.

Once the widening project is completed, traffic through this particular area of Highway 12 will flow in two eastbound lanes, which at its deepest is 20 feet lower than the westbound lanes,

In this same section, two additional barriers were built to help prevent rock slides. Both barriers reach 55 feet in height.

In the past, this section of Highway 12 was notorious for rock slides. At one point, CALTRANS erected a wire mesh net to prevent further rock erosion, said Moussa.

Moussa confirmed that most of the widening project has been completed, although a few housekeeping items remain before the project can be accepted by a review committee.

"A safety review committee will review the project with a fine-tooth comb before accepting the project," Moussa said.

Moussa said that the committee highlighted a need for hillsides on the westbound side in Napa County to be re-seeded so vegetation can grow and prevent soil erosion.

Other aspects of the project include two water runoff systems built into the hill, which prevents water from pooling on the westbound lanes. Also, an animal crossing was constructed to allow local wildlife to pass under the highway unharmed.

"I was cynical at first (about the animal crossing)," Moussa said with a smile. "During the winter, we could see animal footprints (on the damp concrete), so I was pleasantly surprised."

Moussa said that as far as he knows, the widening project is on time and budget.

"We hope to have the whole (Highway 12 widening) project completed by September 5 but that is if everything goes right and nothing sets us back," Moussa said.